DE1554782A1 - Extruder for plastic compounds - Google Patents

Description

"Extruder for plastic mass" USA priority of February 25, 1964 from U.S. Patent Application No. 347,284 The invention relates to an extruder for Plastic masses to be processed with injection or blow molding devices with a they store ca ier and a torpedo-shaped head movable in it having piston for ejecting the stored plastic material -...

In general, manufacturing advantages can be achieved with continuously operated blow extruders by having a constant amount of the Thermoplastic materials stored in an adjacent cylindrical chamber by means of a roller, which drives the stored material in a predetermined Way in an attached orm pushes. The amount of mass ejected and the The frequency of the discharge can be changed and depends on the one to be formed Subject and after one set in the device-L''ole. Extruderei ;;.-'- nich Usually knows ... ith a multitude of shape profiles and colors of thermoplastics to work. Fo only a shaped profile for a thermoplastic with a certain color is used, 1 @n a change to another plastic material of a different color can be done easily. However, in such a case, it is the one previously used Color can mostly be seen in the newly formed goods for a considerable time, wa @ uf a stubborn residue of the v @ rlergenender. Plastic material in that Extruder. This leads to an undesirable loss of production since the Newly extruded goods are not completely uncluttered in color. Rinse out the extruder could improve the condition a bit, but only at the expense of something essential Loss of both plastic and time.

In the course of the invention it has now been found that d-ss dDs plastic material tends to build up on the torpedo-shaped piston of the accumulator at one point and to set which is opposite to the entrance of the extruder barrel. Just repeated AusstosshAbe can possibly build up residual Kunstatoffmae z. B. to replace a completely new color. The invention has the task based on these shuffling caused by time, labor and material losses to remedy. The above-mentioned extruder succeeds in doing this in the case of the extruder proposed here Kind in that fiction; ; emä. ss the head of the piston circumferentially with a Gutter and its conical Flachindb ... c.ern ;;:.: Ec: intrittsUffi.un '..'. BerlijuLdenKol-. Benbereich @ h the kolesenspitze up to the gutter partially with a recess is. Due to such a piston head profile of the @ eri @ lspeic @ er @ piston, a Thorough flushing of the @@ genuserli @@@@ here side of the Kolsenkopf is enabled.

@@@ renu with a @@@ 01 @@ head with a diameter of up to @ it new hurry. it splashed. @@@@@ al the @erin @@ en resistance takes and about it Area in which of him @us ger @ deaus lies a @ @erialspeicherz mer and not completely flows neatly around the kolten, the piston head according to the invention directs, .. i: 'Z. l: i. . , xi, l: l:? 'dB: 3 ('. ti'C. L::; ie: '. IFW; l. kiiC : I1 ~: E-'r: l, ll: i CL1E.'iiOlt '. ilF ', i'; ZCllIcl, CiB .ijbildu ;; 'escn'Lli-jePlstikKGnjeuudieKolbenHtpitzcnfläche @@ teri ls a bit of a hidden mass @ residue and pushes itrus.rWpc.1? r - .. drr.:ol:.Et-Frbe\"ird'..j..ithabenj:ji3:::ä .. t.'io.ll.'oiLoenun -''-. r. '..' lu "ti. '. rjrluuet Time bi .'-'..... 'b'. ',' Ej .. 'i' .. 'u:' etli-jv'-r: '.. ertt j.ndt = r.ichKunind-Extruderbiri 'erB ; r Bauwei @ e and the erf'i. '. f'.un ,, s'.-'-. 'vcr-sc.-l.-gci'tei.Artineinerbui.iGls'. '.' & if.ee- '-'hJ .'-' n.-u'rufr. = c..emti. \ o .. ',' r :: c: uli; ht <.

Fig. 1 steep seketisei in ei: er te @ lwe @@ e in section i *. '. J' .- e, '..' lTe; .nSitbmijl ... ixr.deriteinMeli & derin gew @ lte @ en Beite @@@ aient @@@@@@@@@@@ the material storage device linked with eikem @@@ like @r at @@@@ lich all @ ewein at Spri @ ,.

@@@ sinsust @@ e is refused.

Fi, 2 is a partially sectioned illustration of another known arrangement, which is mainly used in blow molding and in which is an extruder with a us and a form. ou fig. 3 shows schematically partially in section a form of a piston head of a plunger that has been customary up to now in a material storage device, such as that shown for the extruder in FIGS. 1 and 2 Art is known to be used.

Fili3-. 4 brings in a sonitt view according to the representation the H'ig. 3 shows the piston head of a discharge ram in a material store in FIG Here proposed training a Fio 5 and 6 show the omitted according to the invention The piston spray head of FIG. 4 in two different axial positions in the material store, to illustrate the flow of current in the plastic around the piston head. fig. 7 is a sectional view of FIG. 6 along lines VII-VII and leaves the selected arte Recognize the area of the piston spray head of 4 4 to 6 from the front.

<When extruding by blow molding or injection molding of synthetic material using a material reservoir of the type shown in FIGS. 1 and 2 Art rarely occurs - if at all - that the bullet-shaped one in front Pistons is free and safe from plastic during the spraying process. Some plastic compound practically always remains on the underside of the piston, namely in the section opposite the plastic inlet Wan of the piston surface and will stick In the following working strokes, only pushed forward, stack by piece, through new plastic material. This is of course a disadvantage, since it causes small oil errors to occur the molded or extruded article in question become siciltable. This Mangeh is particularly noticeable when there is a change in color done colla The removal of old plastic material through continuous extrusion of fresh and differently colored plastic is a time-consuming and expensive process. For example, the extruder 10 of Figure 1 is fed through the hopper 11 with plastic chips or plastic granulate filled aged, which mass continuously by means of a Screw 12 is pushed forward, where the melting into a plastic hatch takes place, which then continuously through a line 15 running in the nozzle 14 via a Check valve 27 is pressed into a material storage chamber 15. As shown, is the torpedo-shaped piston 17 of the plunger 18 so. as far as possible r. pressed forward been; this was due to hydraulic pressure exerted on piston 19 in the chamber 20 acts, reached. This pressure is injected through the inlet port 22 and discharged through the outlet port 23. While the piston 17 moves forward is and before he cuts off the lead 13, the plastic material in the Material reservoir not pushed back into the extruder because of the increased pressure be, but only exit through opening 25; dccVentil27 staysunv / irk'L-r-, until the Ruckdrack is sc @ lossed h @. The col. Working period lasts only a few Seconds. After pressing the material completely and withdrawing the plunger; -. 18, the piston 17, which has a conical end face, is withdrawn and with it him a small amount of plasticks material, which adheres to the lower piston surface, at which the influx of new plastic material cannot reach it to clear it up or wash off.

The s sticking of the plastic @, as previously described, also occurs in blow molders 30 Euf using the type shown in Fig. 2, ertorpedoföraigeI.ol.'jn3 of the ram 32 in the material spreader 31 is also something of on its way back withdraw the adhering plastic after disengaging a molding 35, which then according to the inner shape of the mold halves 36 lying next to one another, 37 is inflated by opposing pressure on the rods 39, 40 pressed into their working position. The newly flowing plastic material can neither around the piston 33 still extend the Euf of the underside of its conical surface displace remaining plastic opposite the inlet opening. Usually several extrusions are needed to get the one hanging on the bottom of the piston To remove residue or to change the type of plastic.

The sticking of plastic 42 at a certain point of the extruder is more accurate from that of the larger scale held Fig. 3 can be seen. In it, the piston 17 of the fi ... 1 on its return stroke is in a fully extended position psi shown in the new plastic material through line 13 in the IIü.terialspei .. & rkc.j.imerflickst. The previous hill had not been fully squeezed out through the nozzle outlet 25, and the lasse 42 below c. The piston 17 adheres and firmly between the piston surface and the chamber wall is jammed, moves with the plunger 18 continuously forwards and backwards. These low Uene or the fresh equivalent (amount) tends to be at the bottom stick and sometimes peel off in small pieces to to mix in the L dematori. that by grooving and recessing the piston 17 to completely divert the flow of fresh plastic Material around the basket and the areas around the whole material lightly squeezed out and the flask would remain rinsed clean. Such improvement is shown in Fig. 4 shown by 7.

As can be seen from FIGS. 4 to 7, the piston 17 is circumferentially a channel 44 is provided. Its torpedo-shaped surface is also cut out over a circle from about 15 to 30 ° from the piston outlet to the bottom of the Grue. Rina44Jthrough material removal to a recess46 flattened.This recess46 ensures.continuous Flow of the plastic material, moving the material essentially from the lower one Surface area of the piston 17 is completely removed and expressed. the Recess 46 the lower surface of the piston 17 leads to this permanent flow plastic material coming down from line 13 through the tiller 44 along their circumference and then through the enlarged space formed between the torpedo surface reduced in size below and the outlet opening 25, wherein the flow of material is unattainable by it in previously known embodiments Washes or rinses the lower portion of the piston 17.

The front view of the recessed torpedo surface of the piston 17 is shown in Fig. 7, which is a section of Fig. 6 along the line VII-VII As can be seen, the area recess is in its maxim. len depth approximately ' equal to the channel 44 and runs with its base from the end face of the torpedo to the gutter. The profile of the piston in the lower area is over a small cutout of the piston circumference uniformly from the shoulder 45 of normal diameter up to the outermost end point, as can be seen from FIG. 4. The shoulder 45 normal The diameter is consequently in the lower region of the piston 17 to the bottom of the Pin 44 cut out over a cut of 15 ° to about 30 °. The depth of the Channel 44 is chosen in such a way that a faster fluff of the plastic material, in particular around the piston is made possible, around the area always completely flush free.

The formation of an injection plunger surface proposed here. is Successful everywhere where plastic material is extruded applicable in particular when a colored plastic is used and the Parbe should be changed. The extruder can continue to work while the colored plastic chips or the granules are exchanged, which leads to rejects and wasted time can be reduced considerably.

Claims (3)

Claims: 1. Extruder for plastic masses with a storage device Chamber and an ear-movable piston with a torch-or-head for the Ejecting the secured plastic material, characterized in that the The head of the piston (17) has a circumferential groove (44) and its conical surface in the piston area of the piston tip lying opposite the inlet opening (13) ix-t partially with a recess (46) towards the gutter. 2. Extruder according to claim 1, characterized in that d ss the depth the recess (46) of the conical piston surface is essentially constant and corresponds to the extent of the depth of the groove (44). 3. Apparatus according to claim 1 or 2, characterized in that the recess (46) extends over a circular section of the conical piston tip surface from 15-30 0 L e r s e i t e